Objective: It is generally agreed that alcohol use disorders and panic disorder with (PD[A]) or without agoraphobia (PD) tend to occur within the same individual. However, the cause of this comorbidity remains controversial. Three main explanations are that (1) PD(A) promotes pathologic alcohol use as self-medication, (2) chronic alcohol use and alcohol withdrawal induce changes in the neurochemical system that promote panic, and (3) a third factor, such as familial transmission, promotes both conditions. The aim of this review was to survey the literature in order to determine the validity of these explanatory models.

Data Sources: A review of epidemiologic, family, and laboratory studies was performed. Studies were identified using PubMed (English-language articles published from 1960 to 2006, using the search term alcohol and panic).

Study Selection: Twenty studies were reviewed and selected according to the following criteria: PD(A) and alcohol abuse/dependence diagnosed according to the DSM, no additional comorbidity, use of adult samples, comparison with a nonclinical control group, or application of a crossover design.

Data Extraction: Nonsignificant results or trends only were reported as "no difference." Data on "anxiety disorders" or "substance abuse" in general were not included.

Data Synthesis: In PD(A), alcohol lessens anxious apprehension, thereby decreasing the likelihood of panic. In alcohol use disorders, alcohol increases CO2 sensitivity and may thereby promote panic. In both cases, a significant familial transmission contributes to the co-occurrence.

Conclusion: Findings would seem to indicate that PD(A) and alcohol use disorders can both serve to initiate the other via independent mechanisms. Further studies are warranted.